PROJECTSUMMARY Alcohol use disorders (AUDs) manifest from a convergence of characteristics of the individual, the environment, and the alcohol itself. The affective disturbances associated with alcohol withdrawal are examples of this convergence and represent a critical barrier to successful treatment. Reduction of these affectivedisturbanceshasbeensuggestedtorepresentanimportantconceptualapproachtoreducenegative reinforcement-based alcohol intake in dependent individuals. However, treatment of these affective disturbancesiscomplicatedbydataindicatingreducedefficacyofantidepressantssuchasselective-serotonin reuptake inhibitors (SSRIs) in patients with AUDs, and that these traditional treatments can actually increase alcohol intake in some people;? thus, alternate non-monoamine-based treatment approaches for affective symptoms associated with AUDs are critically needed. Here we will test the novel hypothesis that pharmacologicalaugmentationofendogenouscannabinoidsignalingcouldrepresentaneffectivetreatmentfor negative affective states associated with alcohol withdrawal including anxiety and depression, and could thereby facilitate abstinence in patients with AUDs. We will test the overall hypothesis that 2- arachidonoylglycerol (2-AG)-mediated endocannabinoid signaling reduces anxiety and depressive-like behaviors associated with acute and protracted alcohol withdrawal in a mouse model of voluntary alcohol consumption. To interrogate the underlying mechanism of this effect, we will test the hypothesis that insula cortical-extended amygdala circuits are hyperactive during alcohol withdrawal and that over activation of this circuitiscausallylinkedtotheaffectivephenotypesobservedduringalcoholwithdrawal.Finally,wewilltestthe hypothesis that 2-AG-mediated inhibition of insula-extended amygdala circuit activity represents a key mechanismbywhichendocannabinoidsignalingreducesalcoholwithdrawal-inducedanxietyanddepressive- like behaviors. These data could provide new insight into the neural circuit mechanisms responsible for generating negative affective states associated with alcohol withdrawal, and reveal novel neuromodulatory mechanisms capable of counteracting these processes. If successful, these studies could support advancementof2-AG-basedpharmacologicaltreatmentsforAUDsandco-morbidaffectivedisorders.